1. Field of the Invention
The present invention relates to the fermentation industry, and more specifically relates to a method for efficiently producing L-glutamic acid using a coryneform bacterium.
2. Brief Description of the Related Art
L-glutamic acid is conventionally produced by fermentation using coryneform bacteria belonging to the genus Brevibacterium, Corynebacterium, or the like, which are able to produce L-glutamic acid. In order to improve productivity of these coryneform bacteria, strains isolated from nature, mutant strains, or strains modified by gene recombination are typically used.
To improve the production of L-glutamic acid by coryneform bacteria using gene recombination techniques, it has been reported that the activities of glutamate dehydrogenase, citrate synthase, and pyruvate carboxylase may be enhanced (International Patent Publication WO00/18935), or the activities of α-ketoglutarate dehydrogenase, or α-ketoglutarate dehydrogenase, and isocitrate lyase may be reduced (International Patent Publication WO95/34672 and Japanese Patent Laid-open (KOKAI, JP-A) No. 01-296994), and so forth.
The entire nucleotide sequence of the Corynebacterium glutamicum chromosome has been determined (Appl. Microbiol. Biotechnol., 62 (2-3), pp. 99-109 (2003)). However, about 40% of the 3099 putative orfs in this chromosome exhibit low homology to the corresponding genes of other microorganisms with known functions, and therefore encode proteins with unknown functions. Consequently, the effect of deleting these putative orfs has not been reported.